diff --git a/src/ibunfuck.py b/src/ibunfuck.py
index e1ea7fd..5cbf651 100644
--- a/src/ibunfuck.py
+++ b/src/ibunfuck.py
@@ -28,11 +28,12 @@ def __init__(self, path):
     def _clear_patch(self, patch, processors):
         has_changes = False
         for i, patch_piece in enumerate(patch):
+            length = len(patch_piece)
             for j, hunk in enumerate(patch_piece[::-1]):
                 if not all(p(hunk) for p in processors):
                     continue
 
-                del patch[i][len(patch_piece) - j - 1]
+                del patch[i][length - j - 1]
 
             has_changes = has_changes or len(patch[i]) > 0
 
diff --git a/src/plugins.py b/src/plugins.py
index 0f039f2..f94c26f 100644
--- a/src/plugins.py
+++ b/src/plugins.py
@@ -23,8 +23,14 @@ def _xml_changes(klass, chunk):
     @classmethod
     def _is_valid_dimension(klass, hunk, tag, properties):
         minus, plus = klass._xml_changes(hunk)
+        if any(x.tag != tag for x in minus + plus):
+            return True
+
         if len(minus) == 1 and len(plus) == 1:
             mnode, pnode = minus[0], plus[0]
+            if mnode.tag != pnode.tag or mnode.tag != tag or pnode.tag != tag:
+                return True
+
             is_right_tag = mnode.tag == pnode.tag == tag
             diffs = [abs(float(mnode.attrib[p]) - float(pnode.attrib[p]))
                      for p in properties]